
SERVICE 4WD
If a problem occurs with the four wheel drive system,
this message will appear on the DIC. If this message
appears, stop as soon as possible and turn off the
vehicle. Restart the vehicle and check for the message
on the DIC display. If the message is still displayed,
or appears again when you begin driving, the four wheel
drive system needs service.
SERVICE AIR SUSPENSION
If a problem occurs with the suspension system, this
message will appear on the DIC. If this message
appears, stop as soon as possible and turn off the
vehicle. Restart the vehicle and check for the message
on the DIC display. If the message is still displayed,
or appears again when you begin driving, the air
suspension system needs service.
TURN SIGNAL ON
If a turn signal is left on for 3/4 of a mile (1.2 km), this
message will appear on the display and you will
hear a chime. Move the turn signal/multifunction lever to
the off position. Pressing the select button will
acknowledge this message and clear it from the DIC
display.
CARGO LAMP ON
If the cargo lamp is on, this message will appear on the
DIC and you will hear a chime. Turn off the vehicle
and check the liftgate. Restart the vehicle and check for
the message on the DIC display. Pressing the select
button will acknowledge this message and clear it from
the DIC display.
FUEL LEVEL LOW
If the fuel level is low, this message will appear on the
DIC and you will hear a chime. Refuel as soon as
possible. Pressing the select button will acknowledge
this message and clear it from the DIC display.
CHECK OIL LEVEL
If the oil level in the vehicle is low, this message will
appear on the DIC. Check and oil level and correct it as
necessary. You may need to let the vehicle cool or
warm up and cycle the ignition to be sure this message
will clear. Once the problem is corrected, pressing
the select button will clear this message from the DIC
display.
CHECK WASHER FLUID
If the washerfluid level is low, this message will appear
on the DIC. Adding washerfluid will clear the message.
Pressing the select button will acknowledge this
message and clear it from the DIC display.
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2003 - Sierra Denali

SERVICE 4 WHEEL STEER
If a problem occurs with the 4 wheel steer system, this
message will appear on the DIC. If this message
appears, stop as soon as possible and turn off the
vehicle. Restart the vehicle and check for the message
on the DIC display. If the message is still displayed,
or appears again when you begin driving, the four wheel
steer system needs service.
TRACTION ACTIVE
When the traction control system had detected that any
of the vehicle’s wheels are slipping, the traction
control system will activate and this message will appear
on the DIC. For more information see“Traction Assist”
in the Index.
TRANSMISSION HOT
If the transmissionfluid temperature becomes high, the
message center will display this message.
When the transmission enters the protection mode, you
may notice a change in the transmission shifting
patterns. When the transmissionfluid temperature
returns to normal, the display will turn off and the
transmission shifting patterns will return to normal.Notice:If you keep driving your vehicle with the
transmission TRANS FLUID HOT message
displayed, you can damage the transmission. This
could lead to costly repairs that may not be covered
under your warranty.
The following situations can cause the transmission to
operate at higher temperatures:
•Towing a trailer
•Hot outside air temperatures
•Hauling a large or heavy load
•Low transmissionfluid level
•High transmissionfluid level
•Restricted airflow to the radiator and the auxiliary
transmission oil cooler.
A temporary solution to hotter transmission operating
temperatures may be to let the transmission cool down.
If the transmission is operated at higher temperatures
on a frequent basis, seeScheduled Maintenance
on page 6-5for the proper transmission maintenance
intervals.
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2003 - Sierra Denali

After you clean the player, press and hold the EJECT
button forfive seconds to reset the CLN indicator.
The radio will display --- or CLEANED to show the
indicator was reset.
Cassettes are subject to wear and the sound quality
may degrade over time. Always make sure the cassette
tape is in good condition before you have your tape
player serviced.
Care of Your CDs
Handle discs carefully. Store them in their original cases
or other protective cases and away from direct sunlight
and dust. If the surface of a disc is soiled, dampen
a clean, soft cloth in a mild, neutral detergent solution
and clean it, wiping from the center to the edge.
Be sure never to touch the side without writing when
handling discs. Pick up discs by grasping the outer
edges or the edge of the hole and the outer edge.
Care of Your CD Player
The use of CD lens cleaner discs is not advised, due to
the risk of contaminating the lens of the CD optics
with lubricants internal to the CD mechanism.
Fixed Mast Antenna
Thefixed mast antenna can withstand most car washes
without being damaged. If the mast should ever
become slightly bent, you can straighten it out by hand.
If the mast is badly bent, as it might be by vandals,
you should replace it.
Check occasionally to be sure the mast is still tightened
to the cowl. If tightening is required, tighten by hand,
then with a wrench one quarter turn.
XM™Satellite Radio Antenna
System (United States Only)
Your XM™Satellite Radio antenna is located on the
roof of your vehicle. Keep this antenna clear of
snow and ice build up for clear radio reception.
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2003 - Sierra Denali

Once you are moving on the freeway, make certain you
allow a reasonable following distance. Expect to
move slightly slower at night.
When you want to leave the freeway, move to the
proper lane well in advance. If you miss your exit, do
not, under any circumstances, stop and back up. Drive
on to the next exit.
The exit ramp can be curved, sometimes quite sharply.
The exit speed is usually posted.
Reduce your speed according to your speedometer, not
to your sense of motion. After driving for any distance
at higher speeds, you may tend to think you are
going slower than you actually are.
Before Leaving on a Long Trip
Make sure you’re ready. Try to be well rested. If you
must start when you’re not fresh—such as after a day’s
work—don’t plan to make too many miles that rst
part of the journey. Wear comfortable clothing and shoes
you can easily drive in.
Is your vehicle ready for a long trip? If you keep it
serviced and maintained, it’s ready to go. If it needs
service, have it done before starting out. Of course,you’ll nd experienced and able service experts in GM
dealerships all across North America. They’ll be
ready and willing to help if you need it.
Here are some things you can check before a trip:
Windshield Washer Fluid:Is the reservoir full? Are
all windows clean inside and outside?
Wiper Blades:Are they in good shape?
Fuel, Engine Oil, Other Fluids:Have you checked
all levels?
Lamps:Are they all working? Are the lenses clean?
Tires:They are vitally important to a safe,
trouble-free trip. Is the tread good enough for
long-distance driving? Are the tires all in ated to the
recommended pressure?
Weather Forecasts:What’s the weather outlook
along your route? Should you delay your trip a
short time to avoid a major storm system?
Maps:Do you have up-to-date maps?
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Making Turns
Notice:Making very sharp turns while trailering
could cause the trailer to come in contact with the
vehicle. Your vehicle could be damaged. Avoid
making very sharp turns while trailering.
When you’re turning with a trailer, make wider turns
than normal. Do this so your trailer won’t strike
soft shoulders, curbs, road signs, trees or other objects.
Avoid jerky or sudden maneuvers. Signal well in
advance.
Turn Signals When Towing a Trailer
The arrows on your instrument panel will ash whenever
you signal a turn or lane change. Properly hooked up,
the trailer lamps will also ash, telling other drivers
you’re about to turn, change lanes or stop.
When towing a trailer, the arrows on your instrument
panel will ash for turns even if the bulbs on the trailer
are burned out. Thus, you may think drivers behind
you are seeing your signal when they are not. It’s
important to check occasionally to be sure the trailer
bulbs are still working.
Driving On Grades
Reduce speed and shift to a lower gearbeforeyou start
down a long or steep downgrade. If you don’t shift
down, you might have to use your brakes so much that
they would get hot and no longer work well.
You can tow in DRIVE (D). You may want to shift the
transmission to THIRD (3) or, if necessary, a lower gear
selection if the transmission shifts too often (e.g.,
under heavy loads and/or hilly conditions).
You may also want to activate the tow/haul mode if the
transmission shifts too often. See“Tow/Haul Mode”
earlier in this section.
When towing at high altitude on steep uphill grades,
consider the following: Engine coolant will boil at a lower
temperature than at normal altitudes. If you turn your
engine off immediately after towing at high altitude
on steep uphill grades, your vehicle may show signs
similar to engine overheating. To avoid this, let the
engine run while parked (preferably on level ground)
with the automatic transmission in PARK (P) for a
few minutes before turning the engine off. If you do get
the overheat warning, seeEngine Overheating on
page 5-26.
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Parking on Hills
{CAUTION:
You really should not park your vehicle, with a
trailer attached, on a hill. If something goes
wrong, your rig could start to move. People
can be injured, and both your vehicle and the
trailer can be damaged.
But if you ever have to park your rig on a hill, here’s
how to do it:
1. Apply your regular brakes, but don’t shift into
PARK (P) yet.
2. Have someone place chocks under the trailer
wheels.
3. When the wheel chocks are in place, release the
regular brakes until the chocks absorb the load.
4. Reapply the regular brakes. Then apply your
parking brake and shift into PARK (P).
5. Release the regular brakes.
When You Are Ready to Leave After
Parking on a Hill
1. Apply your regular brakes and hold the pedal down
while you:
start your engine,
shift into a gear, and
release the parking brake.
2. Let up on the brake pedal.
3. Drive slowly until the trailer is clear of the chocks.
4. Stop and have someone pick up and store the
chocks.
Maintenance When Trailer Towing
Your vehicle will need service more often when you’re
pulling a trailer. See the Maintenance Schedule for more
on this. Things that are especially important in trailer
operation are automatic transmission uid (don’t over ll),
engine oil, axle lubricant, belt, cooling system and
brake system. Each of these is covered in this manual,
and the Index will help you nd them quickly. If
you’re trailering, it’s a good idea to review these sections
before you start your trip.
Check periodically to see that all hitch nuts and bolts
are tight.
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Service............................................................5-3
Doing Your Own Service Work.........................5-3
Adding Equipment to the Outside of
Your Vehicle..............................................5-4
Fuel................................................................5-4
Gasoline Octane............................................5-4
Gasoline Specifications....................................5-5
California Fuel...............................................5-5
Additives.......................................................5-6
Fuels in Foreign Countries...............................5-6
Filling Your Tank............................................5-7
Filling a Portable Fuel Container.......................5-9
Checking Things Under
the Hood....................................................5-10
Hood Release..............................................5-10
Engine Compartment Overview.......................5-12
Engine Oil...................................................5-13
Engine Air Cleaner/Filter................................5-18
Automatic Transmission Fluid.........................5-20
Engine Coolant.............................................5-23
Coolant Surge Tank Pressure Cap..................5-26
Engine Overheating.......................................5-26
Cooling System............................................5-29Engine Fan Noise.........................................5-34
Power Steering Fluid.....................................5-34
Windshield Washer Fluid................................5-35
Brakes........................................................5-36
Battery........................................................5-39
Jump Starting...............................................5-40
All-Wheel Drive..............................................5-45
Rear Axle.......................................................5-46
Front Axle......................................................5-47
Bulb Replacement..........................................5-48
Halogen Bulbs..............................................5-48
Headlamps..................................................5-48
Front Turn Signal, Sidemarker and
Daytime Running Lamps.............................5-49
Roof Marker Lamps......................................5-51
Center High-Mounted Stoplamp (CHMSL)
and Cargo Lamp.......................................5-52
Pickup Box Identification and Fender
Marker Lamps...........................................5-54
Taillamps.....................................................5-54
Replacement Bulbs.......................................5-55
Windshield Wiper Blade Replacement
..............5-56
Section 5 Service and Appearance Care
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2003 - Sierra Denali

Additives
To provide cleaner air, all gasolines in the United States
are now required to contain additives that will help
prevent engine and fuel system deposits from forming,
allowing your emission control system to work
properly. You should not have to add anything to your
fuel. Gasolines containing oxygenates, such as
ethers and ethanol, and reformulated gasolines may be
available in your area to contribute to clean air.
General Motors recommends that you use these
gasolines, particularly if they comply with the
specifications described earlier.
Notice:Your vehicle was not designed for fuel that
contains methanol. Don’t use fuel containing
methanol. It can corrode metal parts in your fuel
system and also damage the plastic and rubber
parts. That damage wouldn’t be covered under your
warranty.Some gasolines that are not reformulated for low
emissions may contain an octane-enhancing additive
called methylcyclopentadienyl manganese tricarbonyl
(MMT); ask the attendant where you buy gasoline
whether the fuel contains MMT. General Motors does
not recommend the use of such gasolines. Fuels
containing MMT can reduce the life of spark plugs and
the performance of the emission control system may
be affected. The malfunction indicator lamp may turn on.
If this occurs, return to your authorized GM dealer for
service.
Fuels in Foreign Countries
If you plan on driving in another country outside the
United States or Canada, the proper fuel may be hard
tofind. Never use leaded gasoline or any other fuel
not recommended in the previous text on fuel. Costly
repairs caused by use of improper fuel wouldn’tbe
covered by your warranty.
To check the fuel availability, ask an auto club, or
contact a major oil company that does business in the
country where you’ll be driving.
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